DIP 1015--Deprecation of Implicit Conversion of Int. & Char. Literals to bool--Formal Assement

[Walter Bright]

On 11/13/2018 3:29 PM, Rubn wrote:
> enum : int { a = 127 }

To reiterate, this does not create an anonymous enum type. 'a' is typed as 
'int'. Technically,

`a` is a manifest constant of type `int` with a value of `127`.

 > enum A : int { a = 127 }

`a` is a manifest constant of type `A` with a value of `127`.

Remember that `A` is not an `int`. It is implicitly convertible to an integer 
type that its value will fit in (Value Range Propagation). Other languages do 
not have VRP, so expectations from how those languages behave do not apply to D. 
VRP is a nice feature, it is why:

     enum s = 100;     // typed as int
     enum t = 300;     // also typed as int
     ubyte u = s + 50; // works, no cast required,
                       // although the type is implicitly converted
     ubyte v = t + 50; // fails

In your articles, it is crucial to understand the difference between a manifest 
constant of type `int` and one of type `A`.